Cholesterol Conjugated Elastin-like Recombinamers: Molecular Dynamics Simulations, Conformational Changes, and Bioactivity

Current models for elastin-like recombinamer (ELR) design struggle to predict the effects of nonprotein fused materials on polypeptide conformation and temperature-responsive properties. To address this shortage, we investigated the novel functionalization of ELRs with cholesterol (CTA). We employed GROMACS computational molecular dynamic simulations complemented with experimental evidence to validate the in silico predictions. The ELR^CTA was biosynthesized and characterized by using fluorescence assays, circular dichroism, dynamic light scattering, and differential scanning calorimetry. The in silico and in vitro data showed that CTA promotes the formation of intramolecular hydrogen bonds that favor β-sheet secondary structures. Compared with an unmodified ELR^VKV, CTA enhanced the hydrophobicity and stability of the system, allowing the formation of monodisperse nanoaggregates at physiologically relevant temperatures. Importantly, calorimetry assays revealed that ELR^CTA interacted and intercalated with the lipid bilayers of the DPPC liposomes. To demonstrate the implications of these changes for biomedical applications, ELR^CTA and DPPC-ELR^CTA hybrid nanoparticles were tested with cancer and immune cell lines. Interactions with the cell membranes demonstrated a synergistic effect of the composition and size of the modified recombinamer aggregates on the internalization. The results indicated the potential use of ELR-based nanoparticles for localized and systemic drug delivery. This work sets a new precedent to design elastin-inspired biomaterials with predictable self-assembly properties and develop novel drug delivery strategies.